Ch 52/53

Pataasin ang iyong marka sa homework at exams ngayon gamit ang Quizwiz!

A vehicle has a frozen caliper on the left front wheel. The right front caliper is in good condition. Technician A installs a set of four new pads and a remanufactured caliper on the left side. Technician B installs loaded calipers on the left and right side. Who is correct?

B only

A dust boot seal automatically adjusts caliper piston position.

False

A tire on the verge of slipping produces less friction with respect to the road than one that is locked and skidding.

False

A typical fixed caliper housing is designed with one caliper piston.

False

A wheel speed sensor generates a DC voltage as a toothed ring passes the sensor's coil.

False

Antilock brake systems are highly effective in stopping a vehicle driving over loose snow.

False

Nonintegrated ABS systems do not use an electric pump or accumulator.

False

Pumping the brake pedal quickly during ABS activation will assist the antilock brake system to function properly.

False

Rear disc parking brakes have a mechanism that forces the pads against the rotor hydraulically.

False

Sliding calipers move on bolts or pins.

False

The majority of antilock brake systems are of the integrated design.

False

Large vehicles typically use ______ rotors.

ventilated

The customer complains of a high-pitched squeal whenever the wheels are turning, except when the brakes are applied. Technician A says the pads are worn and need replacement. Technician B says the rotors are scored and must be replaced. Who is correct?

A only

Uneven lug nut torque can cause a pulsating brake pedal.

True

The modulator unit is sometimes called a(n) ______.

all answers are correct

Automatic stability control systems help correct _____ by applying the inner or outer wheel brakes.

both "oversteer" and "understeer"

Linings are ____ to disc brake pads.

both "riveted" and "bonded"

An accumulator ______.

both "stores hydraulic fluid to maintain high pressure in the brake system" and "provides residual pressure for power-assisted braking"

Rotors are typically made from ______.

cast iron

Before removing the master cylinder on an ABS system with a high-pressure accumulator, the accumulator must be discharged by ______.

pumping the brake pedal twenty-five times with the ignition off

What channels the flow of air over the exposed rotor surfaces?

splash shield

What prevents moisture from entering the cylinder bore?

the dust boot

A resurfaced rotor must be _____ inch thicker than the discard dimension to allow for wear.

.015 to .030

Technician A says floating calipers must be removed from the steering knuckle when replacing brake pads. Technician B says fixed calipers must be removed from the steering knuckle when replacing pads. Who is correct?

A only

Technician A says the caliper piston seal prevents leakage of brake fluid between the cylinder bore and the piston. Technician B says the caliper piston seal does not contribute to the piston's automatic adjustment feature. Who is correct?

A only

A brake inspection reveals that the outboard pad is significantly thinner than the inboard pad. Technician A says the problem could be a defective dust boot that caused the caliper to seize. Technician B says the problem could be caused by poor lubrication or deformation of the machined sliding areas on the caliper and/or anchor plate. Who is correct?

B only

After new pads are installed, Technician A breaks in the new pads by making a half dozen or more hard stops from high speed to check whether the brakes will fade when hot. Technician B breaks in the new pads with several gentle to moderate stops, allowing time for the pads and rotors to cool between stops. Who is correct?

B only

Technician A says some caliper designs use only one pad lining per brake assembly. Technician B says some disc brake pads have wear sensors. Who is correct?

B only

Technician A says the wheel speed sensor air gap cannot be adjusted. Technician B says wheel speed sensors can be tested with a lab scope. Who is correct?

B only

Technician A uses a dial indicator to measure parallelism. Technician B uses a dial indicator to measure runout. Who is correct?

B only

Which of the following statements concerning brakes is NOT correct?

Drum brakes resist fading better than disc brakes

When replacing rear pads on actuating-type calipers, the piston must be kept from spinning as the C-clamp pushes the piston back into the caliper bore.

False

With ABS, the brake pedal feel during hard [panic stop] braking is similar to that of a conventional power brake system.

False

A rear disc/drum parking brake uses the inside of each rear wheel hub and rotor assembly as a parking brake drum.

True

A typical floating caliper housing is designed with one caliper piston.

True

ABS pressure modulation works to prevent wheel locking.

True

ABS solenoid valves are electrically operated by signals from the control module.

True

An ABS speed sensor may be located on an axle's differential gear housing.

True

An ATC system controls positive wheel spin by modulating hydraulic pressure applied to the brakes on the wheel that is spinning to slow down the wheel.

True

Brake service on an ABS-controlled vehicle is similar to that of a non-ABS-equipped vehicle.

True

Disc brakes require more force than drum brakes to achieve the same braking effort.

True

During pad replacement, some caliper pistons must be rotated with a special tool to retract all the way into the caliper bore.

True

Electrical sensors on some vehicles advise the driver when the brake pads have worn thin and need to be replaced.

True

Most manufacturers recommend that the caliper mounting pins and their bushings be replaced each time the caliper is removed.

True

Most of the service done to the brakes of an antilock brake system is identical to that in a conventional brake system.

True

Nonintegral ABS systems use a conventional vacuum-assist booster and master cylinder.

True

The ABS pump motor switch turns the pump on and off to maintain 200 to 261 psi (1,379 to 1,800 kPa) of hydraulic pressure in the accumulator.

True

The signal produced by wheel speed sensors can be affected by radio frequency interference (RFI).

True

The splash shield and wheel direct air over the rotor to aid cooling.

True

Two solenoid valves are used to control each hydraulic circuit or channel.

True

When hydraulic pressure is diminished, the caliper piston seal functions as a return spring to retract the piston.

True

The red Brake warning light is NOT turned on when ______.

a fault in the ABS system is detected

What is the name of the gas-filled pressure chamber that is part of the antilock brake system's pump and motor assembly?

accumulator

Which of the following is NOT associated with a pedal pulsation problem?

air in the hydraulic system

Solid rotors are usually found on _____.

both "the front brakes of small, compact vehicles" and "the rear brakes of vehicles with rear disc brakes"

Disc brake rotor conditions are being discussed. Technician A resurfaces the rotor if it has lateral runout, lacks parallelism, or is scored. Technician B resurfaces both the left and right rotors even if only one rotor has problems. Who is correct?

both A and B

Technician A readjusts the wheel bearings before measuring lateral runout. Technician B resurfaces or replaces rotors that have more than 0.003 inch of lateral runout. Who is correct?

both A and B

Technician A says a fixed rotor has an integral hub inside which the wheel bearings are mounted. Technician B says a floating rotor is less expensive than a fixed rotor and can be replaced easily and economically. Who is correct?

both A and B

Technician A says a malfunction of the ABS causes the control module to shut off or inhibit the system. Technician B says a loss of hydraulic fluid or power booster pressure disables the antilock brake system. Who is correct?

both A and B

Technician A says a ventilated rotor helps cool the disc brake assembly. Technician B says the splash shield helps cool the disc brake assembly. Who is correct?

both A and B

Technician A siphons out about two-thirds of the brake fluid from the master cylinder reservoir before beginning work on the pads or calipers. Technician B opens the caliper bleeder screws and runs a hose to a container to catch the fluid that is expelled,.while pushing the pistons back. Who is correct?

both A and B

Technician A uses a C-clamp to push the piston back into its bore when replacing pads. Technician B supports the caliper using safety wire while servicing the brakes. Who is correct?

both A and B

Antilock brake systems can modulate the pressure to the brakes as often as _____ times per second.

fifteen

A fixed caliper _____.

is bolted to the steering knuckle has pistons on both sides of the rotor does not move when the brakes are applied

When the ABS is activated when a wheel begins to lock, the brake pedal should ______.

make you feel a small bump followed by rapid pedal pulsations

On actuating calipers, the piston may have to be rotated before the _____ is (are) installed.

pads

A hard pedal [abnormally high amount of pedal pressure is required to stop the vehicle] normally indicates a problem with the ______.

power brake booster

Which of the following is NOT a component of an antilock brake system?

power steering pump

Brake rotors should be checked for _____.

thickness parallelism runout

A vibration or pulsation in the brake pedal when the brakes are applied is usually caused by ______.

warped rotors [runout]


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